Data storage devices, such as disc drives, typically store information on surfaces of storage media such as magnetic or optical discs. In a typical disc drive, one or more discs are mounted together on a spindle motor. The spindle causes the disc(s) to spin and the data surfaces of the media to pass under respective head sliders that carry a transducer for reading and writing data to the storage media.
The head sliders fly over the storage media at a fly height. With the continual increase in the recording density of storage devices, the fly height decreases. Because of media surface irregularities and operational conditions, decreased fly heights may result in detrimental contacts of the transducer with the media. While microactuators positioned in the head slider may actively control the clearance between the transducer and the media, one of the main concerns with active clearance control is reliable and wear-free contact detection.